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/*
* Nokia RX-51 battery driver
*
* Copyright (C) 2012 Pali Rohár <pali.rohar@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/module.h>
#include <linux/param.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/i2c/twl4030-madc.h>
struct rx51_device_info {
struct device *dev;
struct power_supply bat;
};
/*
* Read ADCIN channel value, code copied from maemo kernel
*/
static int rx51_battery_read_adc(int channel)
{
struct twl4030_madc_request req;
req.channels = 1 << channel;
req.do_avg = 1;
req.method = TWL4030_MADC_SW1;
req.func_cb = NULL;
req.type = TWL4030_MADC_WAIT;
if (twl4030_madc_conversion(&req) <= 0)
return -ENODATA;
return req.rbuf[channel];
}
/*
* Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage
* This conversion formula was extracted from maemo program bsi-read
*/
static int rx51_battery_read_voltage(struct rx51_device_info *di)
{
int voltage = rx51_battery_read_adc(12);
if (voltage < 0)
return voltage;
return 1000 * (10000 * voltage / 1705);
}
/*
* Temperature look-up tables
* TEMP = (1/(t1 + 1/298) - 273.15)
* Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255))
* Formula is based on experimental data, RX-51 CAL data, maemo program bme
* and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671
*/
/*
* Table1 (temperature for first 25 RAW values)
* Usage: TEMP = rx51_temp_table1[RAW]
* RAW is between 1 and 24
* TEMP is between 201 C and 55 C
*/
static u8 rx51_temp_table1[] = {
255, 201, 159, 138, 124, 114, 106, 99, 94, 89, 85, 82, 78, 75,
73, 70, 68, 66, 64, 62, 61, 59, 57, 56, 55
};
/*
* Table2 (lowest RAW value for temperature)
* Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first]
* TEMP is between 53 C and -32 C
* RAW is between 25 and 993
*/
#define rx51_temp_table2_first 53
static u16 rx51_temp_table2[] = {
25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39,
40, 41, 43, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 64,
66, 69, 71, 74, 77, 80, 83, 86, 90, 94, 97, 101, 106, 110,
115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211,
221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415,
437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885,
937, 993, 1024
};
/*
* Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius
* Use Temperature look-up tables for conversation
*/
static int rx51_battery_read_temperature(struct rx51_device_info *di)
{
int min = 0;
int max = ARRAY_SIZE(rx51_temp_table2) - 1;
int raw = rx51_battery_read_adc(0);
/* Zero and negative values are undefined */
if (raw <= 0)
return INT_MAX;
/* ADC channels are 10 bit, higher value are undefined */
if (raw >= (1 << 10))
return INT_MIN;
/* First check for temperature in first direct table */
if (raw < ARRAY_SIZE(rx51_temp_table1))
return rx51_temp_table1[raw] * 100;
/* Binary search RAW value in second inverse table */
while (max - min > 1) {
int mid = (max + min) / 2;
if (rx51_temp_table2[mid] <= raw)
min = mid;
else if (rx51_temp_table2[mid] > raw)
max = mid;
if (rx51_temp_table2[mid] == raw)
break;
}
return (rx51_temp_table2_first - min) * 100;
}
/*
* Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah
* This conversion formula was extracted from maemo program bsi-read
*/
static int rx51_battery_read_capacity(struct rx51_device_info *di)
{
int capacity = rx51_battery_read_adc(4);
if (capacity < 0)
return capacity;
return 1280 * (1200 * capacity)/(1024 - capacity);
}
/*
* Return power_supply property
*/
static int rx51_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct rx51_device_info *di = container_of((psy),
struct rx51_device_info, bat);
switch (psp) {
case POWER_SUPPLY_PROP_TECHNOLOGY:
val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
break;
case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
val->intval = 4200000;
break;
case POWER_SUPPLY_PROP_PRESENT:
val->intval = rx51_battery_read_voltage(di) ? 1 : 0;
break;
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
val->intval = rx51_battery_read_voltage(di);
break;
case POWER_SUPPLY_PROP_TEMP:
val->intval = rx51_battery_read_temperature(di);
break;
case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
val->intval = rx51_battery_read_capacity(di);
break;
default:
return -EINVAL;
}
if (val->intval == INT_MAX || val->intval == INT_MIN)
return -EINVAL;
return 0;
}
static enum power_supply_property rx51_battery_props[] = {
POWER_SUPPLY_PROP_TECHNOLOGY,
POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
POWER_SUPPLY_PROP_PRESENT,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_TEMP,
POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
};
static int __devinit rx51_battery_probe(struct platform_device *pdev)
{
struct rx51_device_info *di;
int ret;
di = kzalloc(sizeof(*di), GFP_KERNEL);
if (!di)
return -ENOMEM;
platform_set_drvdata(pdev, di);
di->bat.name = dev_name(&pdev->dev);
di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
di->bat.properties = rx51_battery_props;
di->bat.num_properties = ARRAY_SIZE(rx51_battery_props);
di->bat.get_property = rx51_battery_get_property;
ret = power_supply_register(di->dev, &di->bat);
if (ret) {
platform_set_drvdata(pdev, NULL);
kfree(di);
return ret;
}
return 0;
}
static int __devexit rx51_battery_remove(struct platform_device *pdev)
{
struct rx51_device_info *di = platform_get_drvdata(pdev);
power_supply_unregister(&di->bat);
platform_set_drvdata(pdev, NULL);
kfree(di);
return 0;
}
static struct platform_driver rx51_battery_driver = {
.probe = rx51_battery_probe,
.remove = __devexit_p(rx51_battery_remove),
.driver = {
.name = "rx51-battery",
.owner = THIS_MODULE,
},
};
module_platform_driver(rx51_battery_driver);
MODULE_ALIAS("platform:rx51-battery");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_DESCRIPTION("Nokia RX-51 battery driver");
MODULE_LICENSE("GPL");
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